Certain phenoxy-phenoxyalkane carboxylic acids and derivatives thereof are disclosed in U.S. Pat. No. 3,954,442 to exhibit an excellent selective herbicidal effect against weed grasses in crop plants but to affect broad-leafed plants to only a small extent. Said patent further discloses that such compounds do not damage crop grasses and can be used to combat weed grasses in such crops as well as in dicotyledonus crop plants.
U.S. Pat. No. 4,070,177, on the other hand, discloses phenoxy-phenoxyalkane carboxylic acids and derivatives thereof having herbicidal action to control the growth of broad-leafed weeds in gramineous crops.
However, neither patent discloses any other biological action of such compounds. In particular neither patent discloses the use of such compounds to increase the sugar content of plants such as sugarcane (Saccharum officinerum) or sorghum (Sorghum vulgare). Increased sugar content, of course, increases the value of such plants.